Is It Possible to Have a Sun Allergy?

Understanding Photodermatoses and True Sun Allergy

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People regularly get allergies from things like pollen, pet dander, peanuts, latex, and shellfish, but the one that would seem unlikely is an allergy to sunlight. However, researchers are now just starting to understand how common sun allergies—more accurately referred to as photodermatoses—really is.

In fact, a 2011 study from the Universität Witten-Herdecke Center of Dermatology in Germany suggested that between 10% and 20% of people in the United States., Scandinavia, and Central Europe has experienced the most common form of the disorder known as polymorphous light eruption (PMLE).﻿﻿


This is not to say that all skin reactions to the sun are true allergies. While some people do, in fact, have hypersensitivity to sunlight, other "sun allergies" are caused by medications or topical substance that cause a reaction on the skin when exposed to sunlight.

Symptoms of photodermatoses vary by type. For example, individuals with actinic prurigo, an inherited form of sun reactivity, develop itchy crusty bumps, while those with photo allergic reaction, which occurs when a chemical applied to the skin interacts with UV light, presents with a burning, itchy rash and fluid filled blisters.﻿﻿


Scientists are not entirely sure why people experience reactions to the sun but believe that genetics play a key role in some cases. As with all allergies, photodermatoses is caused when an otherwise harmless substance—in this case, sunlight—triggers an abnormal immune response.﻿﻿

There are over 20 different types of photodermatoses. Some are common and others are rare. These include sun-induced skin reactions in people with known autoimmune disorders such as lupus) and chronic skin conditions that worsen when exposed to light.

Polymorphous Light Eruption

Polymorphous light eruption (PMLE) is the most common type of photodermatoses. It is called polymorphous because the appearance of the skin reaction can vary from person to person.﻿﻿

PMLE skin lesions typically develop several hours to days after sun exposure. They will appear as raised, reddened patches accompanied by itching and sometimes burning.﻿﻿

The rash most commonly affects parts of the body that may have been hidden from the sun in the winter and then become exposed in the summer; this includes the arms and upper chest.

They will often become papular in nature (characterized by raised bumps with no visible fluid). The lesions usually disappear spontaneously within several days and do not leave behind any traces. Oral antihistamines can help relieve itching but do little to improve the actual rash. In severe cases, physicians may prescribe topical or even short courses of oral corticosteroids for treatment. In most cases, time alone will resolve the condition.﻿﻿ PMLE is not considering life-threatening.

Solar Urticaria

Solar urticaria is a rare, chronic form of sun-induced photodermatoses. People with this condition will experience itching, redness, and hives on the areas of skin exposed to sunlight. While symptoms are sometimes confused with a sunburn, solar urticaria can develop within minutes and goes away much quicker (usually less than a day) after the sun exposure has stopped.﻿﻿

Solar urticaria is rare but can be life-threatening in some cases, particularly if large areas of the body are exposed to the sun simultaneously. People have been known to experience a deadly, all-body allergic reaction, known as anaphylaxis, in response to sun exposure.

If anaphylaxis is suspected, emergency medical attention should be sought. If left untreated, anaphylaxis can lead to respiratory failure, seizures, shock, coma, and even death. In affected patients, avoidance of sunlight is the best means of protection.

Cholinergic Urticaria

Cholinergic urticaria is a form of hives caused by an increase in body temperature. This not only includes exposure to sunlight but anything that can raise the body temperature as a whole, including hot showers, exercise, spicy foods, or being overheated at night.﻿﻿

The best treatment for cholinergic urticaria is antihistamines. Non-sedating antihistamines such as cetirizine (generic for Zyrtec) are typically the first line treatment for cholinergic urticaria. If symptoms are refractory to non-sedating antihistamines, hydroxyzine (which usually makes people quite sleepy) may be tried under physician direction.

Cholinergic urticaria is differentiated from PMLE and solar urticaria in that the reaction is not triggered UV rays but by temperature. Even strong emotions can trigger cholinergic urticaria in that they raise body temperature ever so slightly.

Sunscreen Allergy

While contact dermatitis to sunscreen is not as common as an allergy to cosmetics, it is actually not all that uncommon. Known as photoallergic contact dermatitis, the condition is characterized by a reaction to a topical agent (such as sunscreen, insect repellent, lotions, or fragrances) only when the skin to which it has been applied it is exposed to UV light.﻿﻿

The skin reaction can occur on any part of the body where the substance is applied but is usually more pronounced on sun-exposed areas. These include the face, the “V” area of the upper chest and lower neck, the backs of the hands, and the forearms. Avoidance of the product is the best course of treatment for this condition.


Most individual episodes of sun allergy resolve on their own with time. Skin balms such as calamine lotion and aloe vera can help alleviate discomfort, particularly if scaling or crusting occur. Pain can often be treated with a nonsteroidal anti-inflammatory drug like Advil (ibuprofen). More severe cases may require systemic or topical steroids to help bring down the swelling.

Whatever the cause, people with a known sun allergy should make every effort cover up or stay indoors whenever the sun is at its strongest. Sunscreen rarely provides protection from photodermatoses and, in some cases, can make it worse.

When to Call 911

Seek emergency care if some or all of the following occur after sun exposure:

  • Severe rash or hives
  • Shortness of breath
  • Wheezing
  • High fever
  • Fast or irregular heartbeat
  • Nausea and vomiting
  • Confusion
  • Swelling of the face, throat or tongue
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Article Sources
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  2. Cleveland Clinic. Sun allergy. Reviewed January 16, 2018.

  3. Harvard Medical School. Sun allergy (photosensitivity). Harvard Health Publishing. October 2018.

  4. National Health Service. Polymorphic light eruption. Reviewed May 24, 2018.

  5. MedlinePlus. Polymorphous light eruptions. Reviewed April 16, 2019.

  6. Badri T, Schlessinger J. Solar urticaria. StatPearls (Internet). Updated April 11, 2019.

  7. Ngan V. Cholinergic urticaria. DermNet NZ. 2006.

  8. London S. Expert offers insight on photocontact dermatitis. November 22, 2013.